The present specification generally relates to communication devices. More particularly, the present specification describes an acoustic guide for audio transducers.
Communication devices are presently being extensively utilized in a wide range of applications. Communication devices typically include a ringer enabling a user to receive audible notification of incoming calls. Manufacturing the communication device requires a way of acoustically coupling the transducer to the housing.
Audio transducers for generating audio tones are used as ringers in a cellular telephone. The ring tone needs to be loud enough to be heard. However, government regulations prohibit the ring tone from going towards the user""s ear. Unfortunately, typical audio transducers for mounting on printed circuit boards emit their maximum audio levels in a direction perpendicular to the printed circuit board. The sound emitted from the transducer reflects off the inner surface of the housing enclosing the circuit board and bounces around inside the housing. As a result, the sound coming out of an audio port opening in the housing is often muffled and attenuated.
The inventor noticed that to improve the ringing efficiency of a communication device, it is advantageous to provide an acoustic guide between a printed circuit board mounted audio transducer and an audio port opening on the side of the telephone housing. Ringing tones are emitted from the side of the transducer. The tones are acoustically guided through a resonant cavity formed by a hole on the side of the acoustic guide and an opening on the side of the transducer.
The present disclosure describes a receptacle for acoustically guiding tones emitted from the side of the transducer. The receptacle is mounted onto an acoustic transducer within a housing for acoustically sealing and guiding sound from the transducer. The receptacle has a depression on the bottom surface adapted for mating with and sealing the acoustic transducer. In a preferred embodiment, the sidewalls of the depression are inclined at approximately one degree.
An acoustic waveguide is formed by a resonant cavity on one side of the receptacle. The resonant cavity abuts an opening of the transducer on one side and an audio port opening of the housing on the other. In a further preferred embodiment, the physical volume of the resonant cavity is optimized to match the acoustic wave impedance with the operating frequency of the acoustic transducer. The acoustic waveguide formed by the resonant cavity diverts sound from the acoustic transducer at approximately 90 degrees from the perpendicular.
A plurality of standoff features is. formed on top of the receptacle. The plurality of standoff features provide optimum compression to the receptacle such that compression provides acoustic and weatherproof seal as well as shock and vibration absorption for the transducer. In another preferred embodiment, the plurality of standoff features has different heights to accommodate the curvature of the housing. In a particular embodiment, there are four standoff features.
In a further particular embodiment, the receptacle includes a tab formed on a side of the receptacle. The tab is used for easy removal of the receptacle from the transducer. The receptacle is molded as one piece of elastomeric material.
The present disclosure also describes a phone handset. The handset includes a housing, a printed circuit board, an acoustic transducer, and a receptacle as described above.
The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other embodiments and advantages will become apparent from the following description and drawings, and from the claims.